Omega Engineering OM-DAQ-USB-2401 manual Measurement Duration, Scan Time, and Resolution

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NOTE:

In DAQ applications, thermocouples should not be connected single-ended. Doing so can result in noise and false readings. This is especially true when acquiring other high-amplitude signals in conjunction with thermocouple signals that are connected single-ended.

The DAQ units include built-in cold-junction compensation (CJC), which is automatically invoked when you select TC measurements. The OM-DAQ-USB- 2401 automatically converts acquired voltage readings into compensated- linearized temperature readings. This DAQ system can make thermocouple and volts measurements concurrently.

OM-DAQ-USB-2401

TERMINAL BLOCK

(PARTIAL)

A	A	C	A	A
1	1	O	2	2
H	L	M	H	L

V1

V2

COM

V3+

V3

V3-

Figure 4-26. OM-DAQ-USB-2401 Single-Ended and Differential Connections to

Analog Input Channels Diagram

Figure Notes: *V1 and V2 are single-ended inputs.

*V3 is a thermocouple and is a differential input.

4.9 Measurement Duration, Scan Time, and Resolution

In relation to sampling analog input, the terms measurement duration, sample rate, and resolution have the following meanings:

Measurement duration (per channel) – the amount of time used for sampling a channel’s input signal. The measurement durations for the OM-DAQ-USB-2401's analog channels range from very slow (400 milliseconds for one measurement duration) to very fast (1 millisecond for one measurement duration).

Scan Time (per scan) - The amount of time used for scanning (sampling) all selected channels’ input signal. For the OM-DAQ-USB-2401, the scan rates range from very slow (1 hour per scan) to very fast (1 milliseconds per scan).

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